Why is that can of cranberry sauce upside down anyway?

Cranberry sauce is always canned upside down — and here’s why. “The rounded end of the can is filled with an air bubble vacuum, which makes it easier to get the sauce out,” an Ocean Spray representative told Delish. So, the next time you flip over and open a can of cranberry sauce, you’ll know exactly why it needs to be inverted first.

The bubble end of a can of cranberry sauce has an air pocket. When opened, if a consumer slides a knife around the sauce, the vacuum is broken, and the air escapes, helping the jellied cranberry slide out in one piece. It’s a clever application of science that might have gone over many people’s heads, but ultimately, it’s a joyful act that produces a satisfying canned-shape log.

So, if you’ve ever wondered why cranberry sauce labels are upside down, now you know. Also, if you’re in charge of the cranberry sauce ala Bart this year, remember the trick for serving a perfect, single piece on the plate.

Canned cranberry sauce got its start in 1912 when cranberry growers Marcus L. Urann and Elizabeth Lee started working together to create a jellied sauce, which was concocted by boiling the bruised berries from the bog (say that 3 times fast).